Background: The gene for kallikrein-like serin protease, prostate-specific antigen (PSA), has been a candidate gene in several studies. It is known that androgens are important in the proliferation and development of prostate gland and they are the main regulators of PSA expression. The polymorphism of the ARE-I locus on the PSA gene was studied in prostate cancer patients to determine a possible relationship of that locus to prostate cancer risk. Patients and Methods: Forty-nine prostate cancer patients and forty-seven healthy control subjects were compared. Total and free PSA levels were measured by an enzymatic immunassay method. PSA ARE-I polymorphism analyses were performed using a previously described PCR-restriction fragment length polymorphism (RFLP) method. Results: There were no significant differences between the control and patient groups for an), of the PSA-AREI genotypes, but the G allele carriers had a 2-fold higher risk of developing advanced prostate cancer. Conclusion: G allele carriers have a higher risk of developing advanced prostate cancer. With further research, such PSA-AREI polymorphism analyses may help in follow-up and in deciding the prognosis of prostate cancer patients.